In the prior art, semiconductor wafer processing machines generally performed one function only, e.g., sputter coating, etching, chemical vapor deposition etc., or performed limited multifunctions. Cassettes of wafers were carried by operators from one machine to another for different processes. This exposed the wafers to dust and gases during the transfer and required additional time for vacuum pumping at each machine.
A processing machine which could combine multiple processes in the same vacuum environment would probably have to have some mechanism for transporting wafers internally in a horizontal position between work stations. On the other hand sputter coating is best performed with the wafer in a vertical plane to avoid adherence of dust. Therefore, a sputter apparatus in a large multifunction machine would require a means for translating a wafer from a horizontal position to a vertical position for processing and back to a horizontal position.
Sputter processing machines in general have the problem that the machine inherently coats the support apparatus holding the wafer thereby creating mechanical problems and a source of dust. The support apparatus must therefore be periodically cleaned. In most prior art machines, the entire machine must be exposed to the atmosphere during cleaning thereby creating problems of contaminating the sputter source.